USB port may stop working after removing or inserting USB device
SUMMARYWhen a USB device is repeatedly inserted and removed, the USB
port may stop responding. This article describes how to resolve this problem with a
unresponsive USB port. SYMPTOMSIf you quickly and repeatedly insert and remove a USB
device, the USB port may stop responding. When the port is in this state, it no
longer recognizes any USB device. CAUSEThis problem may occur because of a race condition in the
Selective Suspend feature of USB. Microsoft and the hardware vendors that
manufacture the chips that are used for USB have investigated the problem.
However, the results have been inconclusive because of the intermittent nature
of the problem. RESOLUTIONTo resolve this, follow these steps:
WORKAROUNDImportant This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: 322756 (http://support.microsoft.com/kb/322756/) How to back up and restore the registry in Windows To prevent this problem for server products where power management is not important or required, you can disable the selective suspend feature of USB. To do this, you must modify the following registry entry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\USB Note If this registry key is not present, you must create it.
Entry: DisableSelectiveSuspend Type: DWORD Value: 1 disables selective suspend. 0 enables selective suspend This setting affects all USB host controller drivers in the system. If the DisableSelectiveSuspend value is set to 1, the selective suspend feature is turned off and the Allow the computer to turn off this device to save power check box does not appear on the Power Management tab for the USB Root Hub. STATUS
Microsoft is researching this problem and will post more information in this
article when the information becomes available.
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